Category Archives: Life & Health

I had the privilege of following Ben Brookes onto the Exceedance main stage in 2015. I can’t remember a word of my talk, but something Ben said while I was watching him from the green room has stayed with me ever since:

“Some, like Aubrey de Grey, believe that the first person to live to 1,000 has already been born.”

If that sounds to you like the claim of an oddball biogerontologist, you’re not alone. I for one remember scratching my head quizzically at the time.

All the same, it certainly got me thinking. If we’re going to live that long, we’re going to need something worthwhile to keep us busy. We’re all going to need to find a purpose; a focus for our energies.

Let’s start by celebrating goal achievement. Last week, Jeff Bezos’ Blue Origin rocket successfully took off—and then returned back to Earth. Mission accomplished. But, from 100 kilometers above the Earth’s surface, looking back at our planet, what’s the state of our global goal achievement? Do we even have goals?

I ask this as over 50,000 delegates descend on Paris this week for the 21st Conference of the Parties to the United Nations Framework Convention on Climate Change. Or more simply, COP21.

COP21 offers the unique prospect of 196 countries achieving a (sort of) legally binding agreement on climate change: to keep global warming below 2°C by reducing greenhouse gases. But what would a “good goal” for COP21 look like and would it ever be achieved?

Set your goal. Measure it. Achieve it.

It’s easy to get cynical about achieving BHAGs (Big Hairy Audacious Goals), but maybe a template for success has emerged. In 2000, the United Nations agreed to eight BHAGs through its global Millennium Development Goals. Goal number four was to reduce child mortality by two-thirds within 15 years across 138 developing countries.

A 50% reduction in child mortality in 15 years

In 2010, Hans Rosling’s celebrated TED talk outlined a two million annual reduction in child deaths under the age of five within a decade, down to 8.1 million per year. By the end of 2015, we will be below six million deaths per year, almost halving in 15 years. That’s still too high, and many countries will miss the two-thirds reduction target, but nonetheless it is a huge improvement.

As Rosling points out, the Millennium Goals were strong due to measurable targets. Clear targets, at individual country level, have driven the ability to lobby for increases in financial resources for clean water, immunization and antibiotics, motivated by strong partnerships and innovations in service delivery.

A goal for climate change

Rio in 1992 is remembered for establishing climate change as being caused by humans, and more specifically, primarily the responsibility of the industrialized countries.

France, as host, wants to build on the momentum of Rio, but also learn lessons from past summit failures. So, much of the COP21 framework has been defined and negotiated in advance. Francois Hollande has already agreed with top-polluter China on a mechanism to monitor cuts every five years.

The squabbling that characterized Copenhagen in 1999 will be minimized, and high expectations set for those attending, such as encouraging heads of state to arrive at the start, rather than jetting in at the end.

Frequent communication with every country participating has been critical. As conference chair, Laurent Fabius, French Foreign Minister told the FT last week “Negotiators sometimes hold firm positions that only ministers can unlock, I know their bosses – I see them all the time. We talk often, it helps”.

Infographic: Who has pledged an INDC so far, and what percentage of the world’s emissions are covered. Credit: Rosamund Pearce, Carbon Brief, based on EU data

Paris will pull out all the stops to get an agreement, but will we be willing to accept the short-term costs and constraints to slow down climate change? The answer is probably yes.

So what are the lessons for COP21?

As Jeff Bezos’ Blue Origin extreme rocket recycling shows, individual changes in our daily behavior such as recycling and energy conservation can affect climate change, but ultimately, changes need to be government led, especially around energy generation and emission control. Whether world leaders are ready to be held legally accountable for missing their climate goals is an ongoing issue.

Nonetheless, as the Millennium Goals show, clear and well-defined targets, annually measured (“are we there yet?”) create momentum to drive change forward. The success of COP21 will be defined by whether emerging sub-goals are specific, measurable, achievable, realistic, and time bounded. Now that would be smart.

The suicide armed and bomb attacks in Paris on November 13, 2015 were unprecedented in size and scale. The attacks that killed more than 125 people and left 350 injured have exposed France’s vulnerability to political armed violence and alerted the rest of Europe to the threat of salafi-jihadist within their domain.

The Eiffel Tower was lit in the colors of the French flag in a tribute to the victims. Source: Reuters

What is surprising is the magnitude and scale of these six assaults. These attacks were very ambitious. Divided into three distinct groups, the militants were able to execute simultaneous strikes on six locations. Simultaneous attacks are very effective as they cause significant number of casualties before the security services have the time and ability to respond. The attacks were also very well coordinated and involved myriad attack devices reflecting a sophistication that can only come from having some level of military training and expertise as well as centralize control.

2. A well-coordinated attack with unprecedented magnitudes and scale

In the first series of attacks, three bombs were detonated at locations near the Stade de France, where a soccer match between France and Germany was taking place. These bombings killed five people. The three explosions at the Stade de France outside Paris were all suicide bombings. One of the attackers had a ticket to the game and attempted to enter the stadium when he was discovered wearing a suicide bomb vest. He blew himself up upon detection. The second suicide bomber killed himself outside the stadium few minutes later while a third suicide attacker detonated explosives at a nearby McDonalds.

Meanwhile at the same time, gunmen reportedly with AK-47 assault rifles opened fire on a tightly packed Southeast Asian restaurant in a drive-by shooting, killing more than 10 people. Later in the evening there were two other drive by shootings in the different parts of the city that resulted in the deaths of 23 people. Another suicide bomb blast also occurred along the Boulevard Voltaire at a cafe, killing himself but also injuring 15 customers.

The worst violence occurred at the Bataclan Theater, where four militants took hostages during a concert performance by an American rock music group. Witnesses reported that the attackers launched grenades at people trapped in the theater. All the assailants were reported dead after the French police raided the building. Three of the assailants blew themselves up with suicide belts instead of getting arrested, as the police got close while the remaining one was shot and killed by the French authorities. More than 80 people were believed to be killed at the theatre suicide siege.

3. Chosen strategy offers greatest impact

The suicide armed attacks or sieges witnessed at the Bataclan Theater involved a group opening fire on a gathering of people in order to kill as many as possible. Similar to the Mumbai attacks in 2008, the ability to roam around and sustain the attack, while being willing to kill themselves in the onslaught, makes such terrorist attacks more difficult to combat. From the terrorist’s perspective, these assaults offer a number of advantages, such as greater target discrimination, flexibility during the operation, and the opportunity to cause large numbers of casualties and generate extensive worldwide media exposure.

It is possible that following the success of Friday’s Paris attacks, suicide-armed assaults and bomb attacks will become an even more attractive tactic for terrorist groups to replicate. Such attacks will typically target people in crowded areas that lay outside any security perimeter checks such as those of an airport or at a national stadium. Probable targets for such attacks are landmark buildings where there is a large civilian presence.

4. Use of TATP explosives indicates high levels of experience

Also of interest is the terrorist’s use of triacetone triperoxide (TATP) explosives for the suicide bomb vests used in the attacks at the Stadium as well as the Bataclan Theater. TATP is basically a mixture of hydrogen peroxide and acetone with sulfuric, nitric, or hydrochloric acids. These are chemicals relatively available in neighborhood stores. However, TATP is highly unstable and is very sensitive to heat as well as shock. More often than not TATP will detonate prior to the desired time. Given the high level of precision and coordination needed to orchestrate these attacks, an experienced bomb maker had to be involved in creating the suicide bomb vest stable enough to be used in these operations.

5. Longstanding ethnic tensions fueled

The Islamic State (IS) has claimed responsibility for the catastrophic attacks in the French capital. While these claims have not been officially authenticated, the suicide operations and the synchronous nature of these attacks are consistent with the modus operandi of salafi-jihadi militant groups such as the IS and al-Qaida.

Compounding the threat landscape are indications that many French individuals have traveled to countries such as Syria and Libya to receive paramilitary training. The experience of other Western European countries, which face their own home-grown terrorist threat, has shown that individuals benefiting from foreign training and combat experience can act as lightning rods for local radicalized individuals and provide an addition impetus to orchestrate attacks in their homeland. So far, according to the French authorities it is believe that there is around 400 French citizens in Syria fighting with extremists, making the French among the largest western contingents of foreign fighters in Syria.

7. Potential for subsequent attacks

The November 13, 2015 attacks in Paris, France are the deadliest attacks in Europe since the 2004 train bombings in Madrid, Spain, where 191 people were killed and over 1,800 people were injured.

In regards to the terrorism risk landscape in France, while the suicide bombers have been all killed, the drive-by shooters remain at large. Moreover, despite several arrests in Belgium of individuals allegedly link to the attacks in Paris, it is still unclear whether these detentions have broken up the terrorist network that supported these attacks. Thus, in the short term, subsequent attacks in France or even neighboring countries cannot be discounted.

In my invited presentation on October 22, 2015 at the UK Institute and Faculty of Actuaries GIRO conference in Liverpool, I discussed how modeling of extreme events can be smarter, from a counterfactual perspective.

A counterfactual perspective enables you to consider what has not yet happened, but could, would, or might have under differing circumstances. By adopting this approach, the risk community can reassess historical catastrophe events to glean insights into previously unanticipated future catastrophes, and so reduce catastrophe “surprises.”

The statistical foundation of typical disaster risk analysis is actual loss experience. The past cannot be changed and is therefore traditionally treated by insurers as fixed. The general consensus is why consider varying what happened in the past? From a scientific perspective, however, actual history is just one realization of what might have happened, given the randomness and chaotic dynamics of nature. The stochastic analysis of the past, used by catastrophe models, is an exploratory exercise in counterfactual history, considering alternative possible scenarios.

Using a stochastic approach to modeling can reveal major surprises that may be lurking in alternative realizations of historical experience. To quote Philip Roth, the eminent American writer: “History, harmless history, where everything unexpected in its own time is chronicled on the page as inevitable. The terror of the unforeseen is what the science of history hides.” All manner of unforeseen surprising catastrophes have been close to occurring, but ultimately did not materialize, and hence are completely absent from the historical record.

Examples can be drawn from all natural and man-made hazards, covering insurance risks on land, sea, and air. A new domain of application is cyber risk: new surprise cyber attack scenarios can be envisaged with previous accidental causes of instrumentation failure being substituted by control system hacking.

The past cannot be changed—but I firmly believe that counterfactual disaster analysis can change the future and be a very useful analytical tool for underwriting management. I’d be interested to hear your thoughts on the subject.

Recent articles from two separate research groups published in Scienceand Nature Medicinereport major breakthroughs in flu vaccine research. The advances could ultimately lead to the holy grail of influenza prevention–a universal flu vaccine.

By conferring immunity against large numbers of flu strains, the new vaccines have the potential to reduce the severity of seasonal flu outbreaks and vastly reduce the risk of novel pandemics. Using the RMS Infectious Disease Model, we calculated that if such vaccines were able to confer immunity to 50% of people globally, the risk of a novel flu pandemic outbreak could be reduced by as much as 75%.

This would be a huge success in reducing the risk of excess mortality events and improving global health. Though I should emphasise that while Edward Jenner invented the smallpox vaccine in 1796, it took until 1980 for smallpox to be eradicated from the wild. Beyond development of effective broad-spectrum vaccines, there is a lot of work to do to make the world safe from flu.

A high proportion of flu victims are the elderly. Significantly reducing deaths from flu would disproportionately reduce old-age mortality. This is particularly interesting; not only is it an important milestone in improving old-age public health, it is also relevant to old-age care and budgeting for retirement too.

Influenza Is The Most Likely Source of Future Pandemic Sickness and Mortality.

In the U.S., in a single flu season, the average number of flu-related deaths is 30-40,000, peaking at 47,000 deaths in previous seasons. This does not take account of the viruses that can cause major pandemics: death tolls in the 1918 “Spanish Flu” event reached as high 50-100 million people worldwide.

Widespread use of a universal vaccine conferring lifelong immunity could eliminate these deaths, making a meaningful contribution to reducing infectious disease mortality.

The marvel of the new vaccines under development is their potential to confer immunity against many strains, including ones that have not yet emerged. They work by using cutting-edge molecular machinery to target the stem of the haemagglutinin protein on the virus’ surface. The vaccines have only been tested on animal models and only on a small scale so far, but have worked well in reducing viral loads and mortality in these tests.

If this breakthrough translates into future vaccines that prove efficacious in clinical trials, these could become immensely powerful in combatting both seasonal flu cases and reducing the likelihood of new flu pandemics.

Today, beyond seasonal flu, there are no vaccines capable of preventing novel flu pandemics. However, the production pipeline for the current seasonal flu vaccine can be put to use in pandemics, with current capacity of pipelines estimated to produce decisive quantities of vaccine within three months of a pandemic outbreak.

As quantified in the RMS Infectious Disease Model, while this current technology has the potential to substantially reduce the total caseload of a pandemic, it is not a panacea. Three months is a relatively long time for highly transmissible viruses, so very large numbers of people could be infected in this interval. Even more infections would happen during the roll-out period before the vaccine has successfully been given to sufficient people to halt the spread. Furthermore, complications could emerge during the production that either mean it takes longer than three months, or that such a vaccine only confers partial immunity.

RMS created the world’s first probabilistic model of pandemic influenza and the first probabilistic model of vaccine development, delivery, and efficacy. The recent breakthroughs in flu vaccine research are welcome news and RMS scientists are closely monitoring the developments.

When a fire breaks out in a city, there needs to be a prompt firefighting response to contain the fire and prevent it from spreading. The outbreak of a major fire is the wrong time to hold discussions on the pay of firefighters, to raise money for the fire service, or to consider fire insurance. It is too late.

Like fire, infectious disease spreads at an exponential rate. On March 21, 2014, an outbreak of Ebola was confirmed in Guinea. In April, it would have cost a modest sum of $5 million to control the disease, according to the World Health Organization (WHO). In July, the cost of control had reached $100 million; by October, it had ballooned to $1 billion. Ebola acts both as a serial killer and loan shark. If money is not made available rapidly to deal with an outbreak, many more will suffer and die, and yet more money will be extorted from reluctant donors.

One of the greatest financial investments that can be made is for the control of emerging pandemic disease. The return can be enormous: one dollar spent early can save twenty dollars or more later. Yet the Ebola crisis of 2014 was marked by unseemly haggling by governments over the failure of others to contribute their fair share to the Ebola effort. The World Bank has learned the crucial risk management lesson: finance needs to be put in place now for a future emerging pandemic.

At the World Economic Forum held in Davos between January 21-24, 2015, the World Bank president, Jim Yong Kim, himself a physician, outlined a plan to create a global fund that would issue bonds to finance important pandemic-fighting measures, such as training healthcare workers in advance. The involvement of the private sector is a key element in this strategy. Capital markets can force governments and NGOs to be more effective in pandemic preparedness. Already, RMS has had discussions with the START network of NGOs over the issuance of emerging pandemic bonds to fund preparedness. One of their brave volunteers, Pauline Cafferkey, has just recovered from contracting Ebola in Sierra Leone.

The market potential for pandemic bonds is considerable; there is a large volume of socially responsible capital to be invested in these bonds, as well as many companies wishing to hedge pandemic risks.

RMS has unique experience is this area. Our LifeRisks models are the only stochastic excess mortality models to have been used in a 144A transaction, and we have undertaken the risk analyses for all 144A excess mortality capital markets transactions issued since the 2009 (swine) flu pandemic.

With this unique experience, RMS is best placed to undertake the risk analysis for this new developing market, which some insiders believe has the potential to grow bigger than the natural catastrophe bond market.

The U.S. is currently experiencing a bout of cold weather in several regions, raising the question: are we in for another polar vortex winter like the bone-chiller we had last year? And if so, why? Here are four things you might not know about the current extreme cold weather streak in the U.S.

The current cold weather isn’t quite another polar vortex in the U.S. – yet.

The polar vortex is a region of Arctic air that rotates around the North Pole in the Northern Hemisphere, trapping and containing the frigid air in its circulation. Every now and then, parts of the rotating pocket of cold air break off into smaller pockets that mobilize southward into regions like North America, bringing with them below-normal temperatures and stormy conditions.

Figure 1: General image of the Polar Vortex. Source: Accuweather.

As of now, the U.S. is not experiencing full-blown polar vortex effects; only part of the big Arctic air pocket has been displaced into the U.S., so it is more accurate to say that the country is experiencing an outbreak of Arctic air. Last year, most of the U.S. experienced exceptionally cold and snowy conditions, particularly east of the Rockies, as a result of the polar vortex. Early seasonal outlooks for this winter have indicated that this type of severe weather pattern is unlikely to repeat, though one cannot rule out more Arctic outbreaks like this one.

You can blame Super Typhoon Nuri in Japan.

Many of the world’s largep-scale climate systems and atmospheric patterns are interconnected. You may not know it, but Super Typhoon Nuri, which impacted Japan earlier this month as one of 2014’s strongest tropical cyclones, has played a key role influencing this recent cold air outbreak. Cold air from the polar vortex is separated from warm air by what’s called the polar jet stream; depending on atmospheric conditions, this jet stream can look flat or wavy. Big storms, like Nuri, can alter the jet stream’s shape, pushing parts further north (creating a “ridge”) or south (creating a “trough”) than normal.

In Nuri’s case, remnants of the storm pushed part of the polar jet stream north over Alaska, creating a strong ridge. This in turn caused a deep trough to develop over much of the central U.S., making way for Arctic air associated with the polar vortex to flow into the lower 48. It is common for storms to affect the jet stream’s shape, but because Nuri was so intense, it influenced the jet stream enough to trigger a prolonged period of unseasonably chilly weather from North Dakota to New York.

Climate change could have something to do with it.

Our climate is changing, but there are differing views on how climate change affects the polar vortex. Some posit that a warming climate may lead to more frequent cold air outbreaks due to increased sea ice melting. This would allow more energy to move into the atmosphere and weaken the jet streams, thereby increasing the likelihood of cold Arctic air escaping southward into regions like North America and Europe.

Other scientists argue that cold air outbreaks are common and part of the natural variation of the climate. They also suggest that it is extremely hard to link a massive, long-term shift in climate (for example, global warming) to individual weather events. It’s also worth noting that the U.S. takes up less than 3 percent of the Earth’s surface, so even though this region is experiencing cold air outbreaks, there are other parts of the world experiencing record heat at the same time.

Other parts of the country could be in for abnormal weather due to El Niño.

Also affecting this winter’s temperatures is the weak central El Niño being forecast; this series of climatic changes happens when the tropical Pacific Ocean, particularly the central and eastern regions, becomes warmer than average. As the ocean gets warmer with respect to its average temperature, the stronger the El Niño signal. El Niño often results in changes to precipitation and temperature patterns throughout the world, including North America, and especially in the winter.

The most common impact is wetter-than-average conditions along the Gulf Coast, warmer-than-average conditions in the Northern Rockies and Pacific Northwest, drier-than-average conditions in the Ohio Valley, and, to a lesser extent, wetter-than-average conditions in California and the southwestern U.S. The weak El Niño forecast means that these impacts are possible, but not likely to be extreme.

As mentioned in my previous blog post, Ebola has the potential to be one of the deadliest epidemics in a century, but the primary area of concern is Western Africa, where the virus is most prevalent. However, as cases pop up in the U.S., concerns are rising, as evidenced by the acute media analysis and discussion around the first case in New York, for example.

Based on RMS modeling, we estimate that there will be between 15 and 130 cases in the U.S. between now and the end of the year—less than 1 case for every 2 million people. Our calculations assume that American medical professionals working with infected people in West Africa will account for the majority of cases. We simulated the number of new U.S. cases based on the existing infection rates among the American medical workers; this technique incorporates our projections for future West African caseloads and medical staff on the ground in the next two months, based on RMS’s epidemic scenario model. We then further modeled the virus’s spread once back in the U.S., taking into account the preparedness and higher quality of treatment facilities here versus the affected countries in West Africa.

The high end of the range is likely a slight overestimate as our calculations exclude automatic quarantining measures that some areas of the US are implementing. These measures can both reduce the number of contacts (people who come into contact with the infected person) for the imported cases, as well as increase the travel burden on U.S. volunteers planning to support the effort in Africa; this in turn could potentially reduce the number of people who actually make it over to the affected region.

The U.S. is prepared to handle the caseload even if it hits the upper range of 130 new cases. At any given time between now and December, specialized Ebola biocontainment facilities will have 11 beds available, which is enough to cope with the maximum weekly caseload in most of (but not all) of our modeled projections. In the more extreme scenarios, we still expect hospitals nationwide that have at least one Ebola treatment bed in place to handle overflow. Even if the reality over the next few months resembles a very pessimistic situation, it will be manageable given the U.S.’s higher capacity for managing cases.

Catastrophe modeling is an art and a science. The interesting, albeit challenging, part about calculating a range for something like this is that so much is contingent on estimates. The very nature of the virus and the exponential way the epidemic spreads means our estimates of the uncertainty in the variables are amplified in the number of cases. Our estimate is largely dependent on when affected regions reach the tipping point, where the number of new daily cases declines rather than increases. Everything is interconnected – the pace at which the epidemic spreads directly affects the tipping point, which then affects the need for treatment and number of professionals, which in turn affects the potential number of cases that can be imported back to the U.S.

As with all catastrophes we model, understanding risk is the first step toward mitigating and managing it.

Ebola is a hot topic in the media right now, with multiple cases being reported outside of West Africa and much confusion among the general public around the reality of the danger. So, are the fear and sensationalism warranted?

The spread of Ebola in West Africa is in part due to misconceptions and fear surrounding the disease and a lack of public health practices. Ebola can be passed solely via bodily fluids; the risk of unknowingly contracting the disease is low.

Fear is prevalent among some West African communities that Ebola is a lie or is being used purposefully to wipe out certain ethnic groups, causing them to hide sick family members from healthcare and aid workers. Customary burial practices, in which family members kiss and interact with the dead, also have contributed to Ebola’s spread. Getting the populace in these countries to trust foreigners who are telling them to abandon their customs has been an uphill struggle.

In more developed countries where health care is more advanced and understood, the chances of transmission are exponentially smaller due to the fact that extreme containment measures are taken. Controlling the spread of the disease comes down to a question of logistics; if the medical community can control the existing cases and trace the contact made with carriers, spread is much less likely. For example, the case in Texas can be contained to one degree as long as every single person in contact with the patient is tracked.

There is also a (speculative) fear of the virus mutating into an airborne pathogen; the fact is, the chances of the virus changing the way it is transmitted, from fluid contact to airborne passage, are very low and of a similar order of magnitude to the chance of emergence of a different highly virulent novel pathogen.

Vincent Racaniello, a prominent virologist at Columbia University wrote:

“When it comes to viruses, it is always difficult to predict what they can or cannot do. It is instructive, however, to see what viruses have done in the past, and use that information to guide our thinking. Therefore, we can ask: has any human virus ever changed its mode of transmission? The answer is no. We have been studying viruses for over 100 years, and we’ve never seen a human virus change the way it is transmitted.”

The tipping point in the modeling of a virus like Ebola is the point where the resources being used to mitigate the threat outpace the increase in new cases. Trying to get ahead of the epidemic itself is like a race against a moving target, but as long as people get into treatment centers, progress will be made in getting ahead of the illness.

So, while Ebola is a very scary and dangerous illness, it is not something that we expect to become a global pandemic. However, while the current outbreak is not expected to spread significantly beyond West Africa, it still has the potential to be the most deadly infectious disease in a century and could have drastic economic impacts on the communities that suffer from Ebola breakouts. In fact, the economic impacts are likely to be worse than the actual impacts of the disease, due to negative impacts to trade and inter-community relations.

The key is to contain it where it is, reach the tipping point as quickly as possible, and to promote safety around existing infected persons. Through travel control measures and the development of several new drugs to combat the virus, the danger of epidemic should be drastically reduced in Africa and, as a result, the rest of the world.

With the current outbreak of Ebola in western Africa, as well as the recent MERS coronavirus and H7N9 avian flu outbreaks, the world is becoming increasingly concerned about the risk of emerging infectious diseases and their potential to cause the next pandemic.

As catastrophe modelers, how do we assess the risk of a pandemic?

To understand the potential dangers of Ebola, it’s helpful to look to the framework we use at RMS to model infectious disease pandemics. The RMS® LifeRisks Infectious Disease Model projects the excess mortality risk for existing infectious diseases, like influenza, as well as infectious diseases that are emerging or have recently appeared, like Ebola. When modeling a disease, we first look at two main criteria: the virulence and the transmissibility of the pathogen responsible for causing the disease. We then take into account mitigating criteria, including medical and non-medical interventions.

Virulence

Virulence is a measure of how deadly a disease is, typically measured by the case-fatality rate (CFR), which is the proportion of people who die from the disease to those who do not. The current Ebola CFR is 55 percent. For comparison, the CFR for bubonic plague typically ranges from 25 to 60 percent. CFR for flu is typically less than 0.1 percent.

Transmissibility

Transmissibility refers to how likely an infected person is to transmit the disease to another person, and is measured in terms of the basic reproductive number, or R₀ of infection, which is the average number of additional infections one person generates over the course of illness. In order to cause an epidemic, R₀ needs to be greater than 1.

The R₀ for the current Ebola outbreak is greater than 1, and the disease will continue to spread. Past Ebola outbreaks have been estimated to be in the 1.3 to 1.6 range, but have occasionally been greater than 5, which is why there is cause for concern. However, Ebola is less transmissible than many other infectious diseases. For example, measles, which is highly transmissible, has an R₀ of greater than 10 in an unvaccinated environment.

Societal and Environmental Factors

Societal and environmental factors can play a large role in transmissibility. In this case, societal and environmental factors in West Africa have contributed to the disease’s spread. For example, traditional burial practices in which families wash the deceased can expose additional people to the virus.

However, the risk of Ebola developing into a pandemic that extends beyond the region is low, due to the standard public health and infection control practices in place in many countries globally. Ebola can only be transmitted via direct contact with bodily fluids, especially blood, which means that caregivers are the primary people who might be exposed to the virus. In many countries including the U.S., the general practice is to treat all blood as potential sources of infection, due to experience with HIV and other blood-borne diseases. In quarantine situations, such as those being used with the American Ebola cases in Atlanta, the likelihood of transmission from a single person is miniscule.

Medical and Non-Medical Interventions

Medical and non-medical interventions mitigate the risk of an infectious disease pandemic. Typical medical interventions for infectious disease include pharmaceuticals and vaccines. Often, there is no specific therapy or drug available for new or emerging diseases. In these cases, we model the effect of supportive care, which includes management of blood pressure, oxygen, and fluid levels. As we’ve seen with the current outbreak, supportive care and the access to healthcare can vary substantially, depending on the region or population. With the exception of experimental treatments, there are no pharmaceutical interventions available for Ebola. Experimental Ebola drugs are not applicable to large populations at this time.

If there are high enough immunization rates, vaccines can reduce or stop the spread of diseases like measles or whooping cough. Unfortunately, a vaccine isn’t currently available for Ebola. Ebola outbreaks occur sporadically and are caused by different virus strains, making vaccine development more difficult.

In addition to vaccines and medical interventions, we account for non-medical interventions when modeling the impact of pandemics. Non-medical interventions include quarantines, school closures, and travel restrictions. Various countries in Africa have begun to implement these methods in hopes of stopping the spread of Ebola. However, these types of countermeasures can often be difficult to time or enforce properly. Ebola can have an incubation period from two days to as long as 21 days.

So, what is the pandemic potential of Ebola?

The current outbreak is now the largest outbreak of Ebola to date, and the World Health Organization (WHO) has designated the outbreak as a Public Health Emergency of International Concern. However, while cases will continue to develop, a global pandemic is unlikely. Even if the disease were to spread to other regions of the world, Ebola is still considered a rare disease and the transmissibility is likely to be much lower due to quarantine and infection-control measures, even if the CFR remains high. We have not seen any community transmission outside of Africa, and this is expected to continue. Ebola is a very serious disease, with devastating consequences to impacted communities. As risk managers, we aim to improve understanding of catastrophes such as pandemic disease so that as a society we can be better prepared to mitigate risk and recover from catastrophes.

Rebecca Vessenes contributed to this post. As a Senior Quantitative Modeler at RMS, Rebecca is involved in the development and parameterization of the LifeRisks longevity models. She recently completed the longevity model for Japan and has worked on determining the correlation structure for mortality improvement between countries. Prior to working for RMS, she led the Financial Modeling group at AIR. Rebecca earned a Ph.D. in mathematics from California Institute of Technology and is an actuary with the Society of Actuaries.